Field of the Invention
The present invention relates to an image forming apparatus.
Description of the Related Art
Conventionally, when document data is transmitted to an image forming apparatus from a terminal device such as a personal computer (PC) to perform printing, the printing has been immediately performed. In this case, printed sheets may remain left until a user goes to the image forming apparatus to get a printed product. Therefore, in recent years, to prevent the printed product from being left, instead of immediately performing printing when document data is received (input), after a user is authenticated in an image forming apparatus, the image forming apparatus performs printing (authentication printing).
There are some image forming apparatuses that have a function of authenticating a user who operates the image forming apparatus. In this case, the image forming apparatus causes a user to log in using a passcode or an Integrated Circuit (IC) card to identify the user who operates the image forming apparatus. By identifying the user, a function to be used, a limit on the number of output sheets, and a customized screen can be prepared for each user.
An authentication print function of an image forming apparatus in which an authentication function is operated permits operations such as display, printing, and deletion only for document data of an identified user. Thus, a document of an authenticated user can be prevented from being read, printed, and deleted by another user.
Further, an authentication function may be used only when a specific function is used so as to limit a user who can use the specific function (hereinafter referred to as functional authentication).
In this case, the image forming apparatus is made operable by any user in a normal case, and user authentication is performed when the specific function is used. While a user can use copying even when not authenticated (the user is hereinafter referred to as an unauthenticated user), facsimile (FAX) is limited to only a specific user, for example. In this case, when a FAX button is pressed, an authentication screen appears to prompt user authentication, for example.
In addition, a guest account may be provided in user authentication. Functions usable by a guest user in this case are often limited. While an authenticated user is enabled to perform color copying, the guest user is permitted to perform only black-and-white copying, for example.
Thus, in authentication printing, control is performed to permit the authenticated user to perform an operation for only a document of the user or a document which the user has been permitted to operate. That is, control is performed so as not to cause an unpermitted document to be operated by the user.
There has been proposed a method for identifying a user by performing face authentication using an imaging apparatus, so as not to print a document of another person even in an account that is assumed to be used by a plurality of users, such as a guest user account (e.g., Japanese Patent Application Laid-Open No. 2012-203517).
In a system configured as described above, when an unauthenticated user or a guest user performs the above described authentication printing, the following problems (1) and (2) occur:
(1) A document to be operated cannot be identified because a user cannot be identified; and
(2) A document of another user can be made operable if all documents are set to be operated, causing security problems.
On the other hand, in a technique discussed in Japanese Patent Application Laid-Open No. 2012-203517, the user can be identified using face authentication even in a guest account. However, a special device for performing face authentication is required.